Large CP violation in charmed baryon decays

We present a systematic numerical study of CP violation in two-body weak decays of antitriplet charmed baryons. In the standard model, the Δ c =1 quark level interactions inducing CP violation for the relevant decays can be grouped into two types, proportional to the CKM matrix elements λq= VuqV^*cq with $q=d$ and $q=b$, respectively. Recent studies have shown that with SU(3)F flavor symmetry, the decay amplitudes, including their strong phases, can be determined by data if contributions from λb are neglected. However, terms proportional to λb must be retained to create interferences that induce CP violation. Some of the λb terms can be recovered in the framework of SU(3)F flavor symmetry, and the CP-violating rate asymmetry ACP is predicted to be of the order of O(10⁻⁴). We find that final state re-scattering effects, which link λd and λb terms, can help recover the missing terms. The re-scattering effects can enhance CP violation by an order of magnitude, with ACP (Ξc⁰ → p K⁻) - ACP (Ξc⁰ → Σ⁺ π⁻) being as large as 1.87 × 10⁻³. This makes it promising to observe CP violation for the first time in baryon decays.